Mechanical-Technological and Fracture Mechanical Properties of the high Grade Pipeline-Steel X80 with Results of Different Pipeline-Projects

2008 ◽  
Vol 52 (5-6) ◽  
pp. 42-50 ◽  
Author(s):  
S. Felber
Keyword(s):  
Mechanical Properties ◽  
Pipeline Steel ◽  
High Grade

The Micro Structural Characteristic Parameters of High Grade Pipeline Steel and its Mechanical Properties

2006 ◽  
Author(s):  
Xiaoli Zhang ◽  
Chuanjing Zhuang ◽  
Lingkang Ji ◽  
Yaorong Feng ◽  
Wenzhen Zhao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Pipeline Steel ◽  
Structural Parameters ◽  
Large Angle ◽  
Lower Bainite ◽  
Granular Bainite ◽  
High Grade ◽  
Pipeline Steels

The microstructure of high grade pipeline steels, including X65, X70, X80, X100, were studied by SEM and EBSD, respectively. It was found that the microstructures of high grade pipeline steels were composed of lower bainite, granular bainite and acicular ferrite. The phases of kinds of pipeline steels were composed of Fe3C, retained austenite and ferrite. And their percentage content, grain size and its distribution were studied respectively also. These micro structural parameters were correlated to the mechanical properties of kinds of pipeline steels. Furthermore, all kinds of angles of grain boundaries were studied, and the relationship between the angles of grain boundaries and mechanical properties was obtained. It was shown that as the improving of the steel grade, the grain boundary including small angle and large angle increased. And only when grain boundary was greater than 15 degree, it was effective to the toughness behavior.

Effect of M/A Constituents on Mechanical Properties of High Grade Pipeline Steel

2011 ◽  
Vol 284-286 ◽  
pp. 1271-1274 ◽  
Author(s):  
Li Xia Zhu ◽  
Xiao Dong He ◽  
Xin Li Han ◽  
Ting Ting Qu
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Impact Toughness ◽  
Room Temperature ◽  
Welded Joint ◽  
Pipeline Steel ◽  
Morphological Changes ◽  
High Impact ◽  
High Grade ◽  
High Tensile Strength

The morphological changes, dimension and distribution of M/A constituent in different region of X80 acicular ferrite pipeline steel were investigated; the effect of M/A constituents of X80 on Charpy V-impact and room temperature tensile properties were also discussed by OM and SEM. The results show that: the distribution and morphosis of the M/A constituents have strongly effect on the mechanical properties. The uniformly distributed massive M/A constituents with chord less than 2 μm observed in grains of base metal, presents high impact toughness and high tensile strength, and the strip M/A constituents with chord more than 2 μm observed in welded joint samples exhibits low impact toughness and high tensile strength. It is seems that the changes of the morphosis and distribution of M/A constituents induce the hardening effect during the deformation which is the main reason to the different mechanical property.

Research of High Grade HIC-Resistant Pipeline Steel

2014 ◽  
Vol 900 ◽  
pp. 730-733 ◽  
Author(s):  
Xiu Hua Gao ◽  
Jing Li ◽  
Chuang Li ◽  
Yan Liang ◽  
Lin Xiu Du ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Boundary ◽  
Pipeline Steel ◽  
Granular Bainite ◽  
High Grade ◽  
Good Resistance ◽  
Corrosion Resistant ◽  
Structures And Properties ◽  
Hydrogen Induced Cracking ◽  
Closed Formation

Carry out research on the processes, structures and properties of the X70 corrosion-resistant pipeline steel and analyze the mechanism of the hydrogen induced cracking. The results show that: the developed steel not only has excellent mechanical properties, but also has good resistance to H2S corrosion. Microstructure of the X70 corrosion-resistant pipeline is mainly the acicular ferrite and granular bainite, with well-closed formation and fine grains. Hydrogen Induced Cracking (HIC) begins with the appearance of the hydrogen blistering on the specimen surface, and cracks generated by the hydrogen blistering gradually extend inward from the surface along the grain boundary, diffuse inside the specimen gradually, and finally form hydrogen induced cracking.

Effect of Boron on Microstructure and Mechanical Property of High Grade Pipeline Steel

2011 ◽  
Vol 299-300 ◽  
pp. 319-322
Author(s):  
Xing Chang Tang ◽  
Yong Lin Kang ◽  
Yan Yan Bo ◽  
Lei Fan
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Tensile Testing ◽  
Pipeline Steel ◽  
Testing Machine ◽  
High Grade ◽  
Tensile Testing Machine ◽  
Static Tensile ◽  
Microstructure And Mechanical Property ◽  
Electronic Microscope

The correlation among boron, microstructure and mechanical property of the X120 pipeline steel was investigated in this study. The mechanical properties of the steels were tested with quasi-static tensile testing machine. The microstructure of the steels with different boron contents was observed with scanning electronic microscope (SEM) and transmission electronic microscope (TEM). The result shows that by adding a small amount of boron the mechanical property of pipeline steel can be improved effectively.

Effect of Ferrite Volume Fraction on Mechanical Properties of X80 Pipeline Steel

2014 ◽  
Vol 989-994 ◽  
pp. 212-215
Author(s):  
J. Liu ◽  
G. Zhu ◽  
W. Mao
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Work Hardening ◽  
Single Phase ◽  
Volume Fraction ◽  
Pipeline Steel ◽  
X80 Pipeline Steel ◽  
Hardening Behavior ◽  
Two Phases ◽  
Better Than

The effect of volume fraction of ferrite on the mechanical properties including strength, plasticity and wok hardening was systematically investigated in X80 pipeline steel in order to improve the plasticity. The microstructures with different volume fraction of ferrite and bainite were obtained by heat-treatment processing and the mechanical properties were tested. The work hardening behavior was analyzed by C-J method. The results show that the small amount of ferrite could effectively improve the plasticity. The work hardening ability and the ratio of yield/tensile strength with two phases of ferrite/bainite would be obviously better than that with single phase of bainite. The improvement of plasticity could be attributed to the ferrite in which more plastic deformation was afforded.

scholarly journals Effect of Annealing Process on the Mechanical Properties of X70 Pipeline Steel

2018 ◽  
Vol 186 ◽  
pp. 02001
Author(s):  
Teng-wei Zhu ◽  
Cheng-liang Miao ◽  
Zheng Cheng ◽  
Zhipeng Wang ◽  
Yang Cui ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Tensile Strength ◽  
Annealing Temperature ◽  
Pipeline Steel ◽  
Annealing Process ◽  
X70 Pipeline Steel ◽  
Grain Sizes ◽  
Scanning Electron

The influence of the mechanical properties of X70 pipeline steel under different annealing temperature was studied. The corresponding microstructure was investigated by the Field Emission Scanning Electron Microscopy. The results showed that the yield strength and the tensile strength both experienced from rise to decline with the increase of annealing temperature. The grain sizes were coarse and a large amount of cementite precipitated due to preserving temperature above 550 °, which induced matrix fragmentation and deteriorate the -10 ° DWTT Toughness. There were little changes on the microstructure and mechanical properties when the annealing temperature was under 500 °.

scholarly journals Experimental Research on Fatigue Properties of X80 Pipeline Steel for Synthetic Natural Gas Transmission

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Li Yan–hua ◽  
Feng Hui ◽  
Chi Qiang ◽  
Fei Fan ◽  
Gao Xiong-xiong ◽  
...  
Keyword(s):  
Natural Gas ◽  
Base Metal ◽  
Hydrogen Content ◽  
Volume Fraction ◽  
Pipeline Steel ◽  
Fatigue Properties ◽  
High Grade ◽  
Long Distance ◽  
X80 Pipeline Steel ◽  
Synthetic Natural Gas

In recent years, many synthetic natural gas demonstration projects have been put into operation all over the world, and hydrogen is usually contained in synthetic natural gas. X80 is the most commonly used high-grade pipeline steel in the construction of natural gas pipelines. The compatibility between high-grade pipeline steel and hydrogen directly affects safety and reliability of long-distance pipelines. Therefore, in order to study the effect of hydrogen content on fatigue properties of high-grade pipeline steel, fatigue specimens were taken from base metal, spiral welds, and girth weld of submerged arc spiral welded pipes, respectively. Specifically, the total pressure was 12 MPa and hydrogen content was from 0 to 5vol%. Experimental results indicate that the hydrogen significantly increases the fatigue crack growth rate for both base metal, spiral weld, and heat-affected zone of X80 pipeline steel for about ten times compared with reference environment nitrogen, hydrogen would greatly reduce the fatigue life of the X80 pipeline steel, and the fatigue lifetime would decrease with the increase in hydrogen volume fraction. In order to ensure the safe operation of SNG pipeline, the hydrogen content should be controlled as low as possible.

Effect of Nanometer Magnesium Oxide Addition on the Cast Microstructure of X80 Pipeline Steel

2013 ◽  
Vol 401-403 ◽  
pp. 610-613
Author(s):  
Jian Ming Wang ◽  
Yang Liu ◽  
Yan Liu ◽  
Qian He Ma
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Magnesium Oxide ◽  
Pipeline Steel ◽  
Harsh Environment ◽  
Second Phase ◽  
X80 Pipeline Steel ◽  
Oxide Addition ◽  
Second Phase Particles ◽  
Cast Microstructure

The pipeline steel as an application in pipeline construction must have good comprehensive mechanical properties due to the harsh environment of the pipeline engineering. So this experiment takes the X80 pipeline steel as the research object, the thermal stability second phase particles which would not be dissolved or aggregated at high temperature will be expected by means of adding nanomagnesium oxide into the steel with the method of carrier dispersion addition. The effect of nanometer magnesium oxide addition on the cast microstructure of X80 pipeline steel was analysed. The results show that the cast microstructure is consist of the ferrite and a small amount bainite. And the bainite is distributed at the boundary of the ferrite grains. When adding 0.02 wt% nanometer magnesium oxides, the number of bainite increases significantly in the cast microstructure, which is mostly distributed at the boundary of the ferrite grains.

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